This work investigates alterations in activity or concentration of various brain enzymes and substrates in response to exposure to anoxia or hypoxia in various areas of cortex, basal ganglia, white matter, and nuclei in the brain stem. Tissue assays are carried out both during and following exposure to anoxia and hypoxia. Comparisions are made of the changes in enzyme activities and substrate concentrations in the brains of animals that develop brain edema and in the brains of those that recover without injury.